1. Field of the Invention
The invention relates to apparatus for forming concrete into various shaped products wherein the apparatus is of a portable nature.
2. Description of the Prior Art
Shaped cement products are typically formed by pouring fluid cement into an open mold having the form of the desired product and allowing the cement to set and harden within the mold. The pouring of the fluid cement into the mold, distribution and tamping of the fluid cement within the mold, and the removal of the hardened product from the mold has generally been a time consuming and expensive process requiring substantial labor. Moreover, in the past a large number of molds had to be utilized in order to produce a plurality of finished products at the same time, thus requiring a large investment in molds or resulting in slowed production because of the unavailability of sufficient molds.
Also, in the past due to the large size of the apparatus necessary to produce a sufficient quantity of blocks, the blocks were necessarily produced at one location and, after curing, shipped to a point where they were needed for construction of a structure. This necessitated a permanent building and transportation of the product to a curing room for quickly curing the blocks in order to move them rapidly through the processing plant. In order to provide for inexpensive blocks, transportation and curing procedures had to be hastened. The movement of the uncured product and the quick curing process of the cement blocks would provide a product which was inferior to a product which is produced by the longer natural curing method of allowing air and sun curing of the cement for a period of up to twenty-eight days.
Examples of prior art block forming machines include U.S. Pat. No. 4,063,859, issued to Halle et al. This reference shows a stationary apparatus for producing shaped concrete products wherein there is included a novel stacker for the concrete blocks. U.S. Pat. No. 3,887,685, issued to Stelzmuller, shows an automatic feed block molding press which is designed to compress granular material into blocks especially electrode blocks. U.S. Pat. No. 3,181,222, issued to Palmer discloses a machine for manufacture of prestressed concrete conduit which uses a unique mold which is resiliently mounted so that high pressure compaction of the concrete will not affect the mold. U.S. Pat. No. 3,142,105. issued to Weir et al, shows a machine for making adobe blocks wherein a distributing mechanism is moved forwardly over a set of molds. The device is designed to provide a mobile completely self-contained machine which will scoop up soil and carry on all necessary mixing to produce mud and distribute the mud in forms for adobe blocks. In the Weir device, material is disposed within the forms and then the forms are lifted to leave a series of blocks to air dry. This machine, however, does not contemplate the more sophisticated requirements necessary in producing concrete blocks and also is not adapted for automatic operation. U.S. Pat. No. 2,859,502, issued to Brown, Jr., shows a a block molding machine which uses two sets of dies, one set of dies being filled with liquid cement and vibrated and tamped while a second set of dies having been vibrated and tamped, is manipulated to eject its blocks upon a seasoning table. This machine is a stationary device and is designed for use in a plant having a special room for curing the blocks. Further devices which demonstrate various techniques for distributing liquid cement and producing blocks include U.S. Pat. Nos. 2,298,458, 2,396,999 and 2,270,829.